Carob tree
Ceratonia siliqua
Botanical family: Fabaceae
Ceratonia siliqua, a tree of the eastern Mediterranean basin, belongs to the Fabaceae family. Its longevity and its resistance to drought make it a pillar of water-thrifty Mediterranean orchards.
Full sun
Chalky, dry, well-drained, tolerates poor soils
Low once established, very drought-resistant
Moderately hardy (~-6 to -7 °C; young spring growth frost-tender from -4 to -5 °C), Mediterranean climate
Frost-tender in your zone
Mostly dioecious: a male tree is needed near the female trees, unless it is a hermaphrodite variety; insects carry the pollen
Needs a male plant near the female plants
Role in permaculture
A Mediterranean evergreen tree, offering a dense shade appreciated in dry orchards. Its sweet pods (carobs), harvested in autumn, are traditionally used dried and ground as a substitute for cocoa or as a food thickener.
Companions
No companion planting is documented for this plant: no recommended neighbour, no neighbour to avoid.
Insects attracted or useful
Seasons & availability
Sown in spring, or grafted for fruiting varieties, the carob gives its sweet pods from late summer into autumn; dried and ground, carob then keeps all year.
Available: January, February, March, April, May, June, July, August, September, October, November, December.
Guidance for the oceanic / temperate climate; it may vary with your region, altitude, exposure and growing method.
Sources
- Batlle, I., Tous, J. (1997), « Carob tree. Ceratonia siliqua L. », IPGRI (cgspace.cgiar.org/items/72528414-be97-4064-a018-bf81b4a0a3a3)
- Tela Botanica, « Ceratonia siliqua L. » (tela-botanica.org/bdtfx-nn-16142-description)
- Plants For A Future, « Ceratonia siliqua » (pfaf.org/user/Plant.aspx?LatinName=Ceratonia+siliqua)
Nutritional & medicinal properties
For educational purposes. Not a substitute for medical advice. Effects depend on the form, the dose and personal context.
Precautions & contraindications
For any health use, rely on medical advice: the traditional claims (transit, cholesterol, blood glucose) are not confirmed by convincing studies. At a high dose, carob and its gum can cause fermentation and digestive discomfort; caution in case of allergy to legumes or tree nuts. In infants, any thickener, including carob flour, must be used only on medical advice.
Family behaviour: Legumes
In general, Legumes fix nitrogen from the air in most cases, thanks to the Rhizobium in their root nodules. They mainly enrich the soil for the following crops, as their residues decompose. Ideal in a rotation, before nitrogen-hungry plants such as nightshades.
But this plant is an exception
A Fabaceae without functional nitrogen-fixing nodules: its genome carries nodulation genes that have become inactive, a sign of lost nodulation (Bibi et al., 2026). Do not count on it as a nitrogen fixer in the garden.
Understanding families means learning one rule per family rather than every pairing one by one. Learn more →
Species & varieties
The best-known species and varieties in France.
Common varieties
Voices of peoples
Paraphrases attributed to their documented sources. Never an invented quote.
The Gospel of Luke (parable of the prodigal son) and the medieval Christian tradition of 'St John's bread' · Eastern Mediterranean in the 1st century, then Christian Europe of the Middle Ages
The seed of the carob, remarkably regular, gave its name to the goldsmiths' carat, from the Greek keration ('little horn'), which also formed the botanical name Ceratonia. In the parable of the prodigal son, he covets the pods (keratia) given to the swine (Luke 15:16), which tradition identifies with carobs. The nickname 'St John's bread' is born of a later belief that John the Baptist fed on carobs in the desert; but most exegetes read the Greek akrides as real locusts, and the equation with the carob remains a popular interpretation, to be distinguished from the text.
Évangile de Luc 15,16 (keratia, les gousses de la parabole) ; étymologie du carat (< grec keration) et du genre Ceratonia (< keras, « corne ») ; notice encyclopédique sur le caroubier (« St John's bread »).
Two registers not to be confused: the etymology of the carat and the mention of the pods in Luke 15:16 are attested; on the other hand, 'John the Baptist ate carobs' belongs to a tradition of interpretation, presented here as legend, not as fact, the locust hypothesis (akrides) being the majority view among exegetes. No health benefit is asserted here.
Keep in mind
The carob tree belongs botanically to the Fabaceae family, but it does not form functional nitrogen-fixing nodules with Rhizobium like most legumes, an exception within the family, documented by classical botany. Avoid attributing to it a nitrogen-fixing role in the garden.
A note on rigour: many companion pairings are gardening folklore; this note sums up what the sources say, where there are any.
Key takeaways
- • Prefers full sun exposure.
- • Ideal soil: chalky, dry, well-drained, tolerates poor soils.